[STEVEI]

just wondering if these can be linked. after reading Johna's website last night i found out that the ecu knows how fast you are going and in what gear. my speedo reads incorrect because i dont have the turbo clocks in and it reads too slow. could this be linked or should i buy a new first gear senesor?

i am running a f28 with mechanical clocks btw

please help as 'limp home mode' is painfully slow!!


ste

 

[LEE69]

The astra GSi takes it speed reading from the ABS or of the back of the dash depending on year.

Does your speed indicator still work ok on the computer?

 

[Mark T]

Either the 1st Gear switch isn't working right or it's the speed signal

Early Cav T and Astra GSI had a speed signal of about 8100 pulses per km generated from a speed sender on the back of the Speedo clocks.

Late Cav T and Astra GSI had a speed signal derived from the ABS NSF wheel speed. (about 16200 pulses per km).

I suspect you have a Late Turbo and Early GSI which may give you some issues!

If that's the Case, then fitting a set of clocks from an Ecotec Astra, will give the required 16200 odd pulses per km.

 

[STEVEI]

speed indicator still works on the computer, my astra is a k reg GSI and the motronic 2.7 is from a calibra on a L reg.

ste

 

[Mark T]

L reg 94? If so it'll have electronic clocks, and expect ~16200 pulses per km.

Get a set of Ecotec clocks, that will sort the speed signal.

You'll then need the trip computer reprogrammed for the different speed signal.

This needs Tech1, Ian V6 can do it.


Mind you, the Fuel Comp will be reading wrong anyway, due to the higher flow injectors you are running.

 

[Andy K]

probably the 1st gear switch. do you have a 6 spd box ?

 

[STEVEI]

Yep its a f28 with mechanical speedo cable.

my brain hurts!

ste

 

[Andy K]

have you just fitted the engine ?

or has it been working fine for ages ?

 

[STEVEI]

just fitted it mate.

if the vehicle speed is taken off the abs this has not changed from its original spec so there should'nt be a problem there i think, and if the vehicle speed from the abs AND the speedo clock both talk to the ecu, when i disconect the speedo cable the engine EML should come on, if it does'nt then the falt lies in the 1st gear selection swicth.

i think this might make sense. ( ?!? ) tell me if it does'nt

should i try disconecting the speedo cable?

ste

 

[Andy K]

what year car did the engine come out of ? Did it have twin airbags ?

Cutting the blue/red wire to the engine ecu will usually shut the light up.

or check that the switch works when 1st gear is selected. It should open when in 1st

 

[STEVEI]

don't know if it had air bags mate.

how i can i tell if the switch is working?

ste

 

[Andy K]

connect a meter upto the swtich on continuity mode.

It should beep all the time except with 1st gear is selected.

The switch is on the bottom of the gearbox at the front

 

[STEVEI]

cheers mate, is that one at the top front of the box the reverse sensor then?

ste

 

[Andy K]

yes